What the app does
Real‑time hydration guidance powered by your Garmin device, personalized to you. Fluid‑Loss Companion estimates your sweat/fluid loss during workouts and builds a personalized model from your past activities to improve accuracy over time.
Who it’s for
- Cyclists and triathletes training on the road, TT, gravel, or indoors
- Riders who want actionable hydration guidance during races and long rides
- Optimized for Garmin bike computers via Connect IQ
Platforms
- iOS Available via TestFlight
- Android Available via Play Store
- Garmin Data field for bike computers via Connect IQ
Key benefits
Personalized accuracy
Improve predictions with your own ride history and measured fluid loss.
Real‑time on your bars
Live estimates sent to your Garmin bike computer every ~2 minutes.
Fast import
Paste or share a Garmin Connect ride URL and add your measured loss in mL.
Simple and focused
No complex setup—pair your device, train your model, and ride.
How it works
Data sources
- Live ride metrics from your Garmin bike computer during workouts.
- Past rides imported from Garmin Connect.
Models
- Generic model: Default predictions without personalization.
- Personalized model: Trained on your own rides (≈10+ rides recommended for a solid first model). The app can auto‑choose the best model or you can pick.
Under the hood
The app securely calls a lightweight cloud service to get your current estimate and to train your personal model—no developer setup needed.
Import from Garmin Connect
Paste or share a Garmin Connect activity URL, then add your actual fluid loss in mL. It only takes a few seconds and directly improves your model’s accuracy.
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Prediction vs Training
Prediction (during workout)
- Pick your Garmin device in the app and start tracking.
- The app receives metrics and calls the cloud predict endpoint every ~2 minutes.
- The fluid‑loss estimate is shown on the phone and sent to your Garmin device.
- Model choice: If you’ve trained a personalized model and your preference is Auto or Always Personalized, the app uses it; otherwise it uses the generic model.
Training (between workouts)
- Import past activities by sharing or pasting a Garmin Connect URL.
- Enter your measured fluid loss (mL) for each activity and save.
- Once you have enough activities (≈10+), tap Train Cloud Model.
- Your personalized model is stored server‑side and used for future predictions.
Interaction with your Garmin device
Device selection
Connect your Garmin bike computer inside the app. Android may request Bluetooth and Location permissions for BLE scanning.
Live metrics
The app receives real‑time ride metrics via the Garmin Connect IQ Companion channel while you work out.
Feedback to head unit
The latest fluid‑loss prediction is sent to your Garmin head unit periodically, so guidance stays visible on your bars.
See the App in Action
A visual tour through the key features and screens
Home Dashboard
Device selection, start tracking, and real-time predictions
Import from Garmin
Paste activity URL and add measured fluid loss
Train Your Model
Build personalized predictions from your ride history
On Your Bike Computer
Live fluid loss data on your Garmin head unit
Join the Beta
Get early access to FluidLoss on iOS and Android. Beta testers keep Pro features free forever.
Data and privacy
- Local storage: Recent activities are saved on your device.
- Cloud: Predictions and training happen via a remote API. Your identity is tied to your paired device ID—no personal profile is required in‑app.
Frequently Asked Questions
FluidLoss works with Garmin Edge bike computers including Edge 530, 540, 830, 840, 1030, 1040, and Explore series.
We recommend at least 10 rides with measured fluid loss across different conditions (temperature, intensity, duration) for an accurate personalized model.
Yes. Your activity data is stored locally on your device. Cloud predictions use your device ID—no personal profile is required. We never sell or share your data.
Beta testers keep all Pro features free forever. This includes personalized ML model training, advanced analytics, and all future premium features. After public launch, new users will need a Pro subscription, but beta testers retain lifetime free access.
Beta testers keep Pro features free forever, even after public launch. Your early support is rewarded with lifetime access to all premium features at no cost.
No extra sensors required. FluidLoss uses existing data from your Garmin device (heart rate, power, temperature, duration) to estimate fluid loss.
Personalized models trained on your own data can approach the accuracy of weighing yourself before/after rides, especially with 15+ training activities across varied conditions.